### M-squared Measurement & Analysis - DataRay

M² Measurement & Analysis.. M², M2, or M-squared, is an important beam quality metric.. In short, it defines how a beam compares to a perfect single-mode Gaussian.. For a given wavelength, there is a relationship between far-field divergence and beam waist diameter that determines M².. For the same far-field divergence, M² values greater than 1 ..